Introduction

Abstract

Imagine you are having a polite conversation with a receptionist when you check into a hotel where you suddenly get the feeling that something is weird. In a flash you realize what’s wrong – this is not a real person but rather a robot. Your first reaction would probably be “It’s unbelievable – she looks so real,” just as you would react to an artificial flower that is a good imitation. With a flower, though, you can touch it to find out if it is real; here, you must rely on your other senses to confirm your suspicion.